Qihong Deng

Human thermal sensation and comfort in a non-uniform environment with personalized heating

BACKGROUNDnThermal comfort in traditionally uniform environment is apparent and can be improved by increasing energy expenses. To save energy, non-uniform environment implemented by personalized conditioning system attracts considerable attention, but human response in such environment is unclear.nnnOBJECTIVESnTo investigate regional- and whole-body thermal sensation and comfort in a cool environment with personalized heating.nnnMETHODSnIn total 36 subjects (17 males and 19 females) including children, adults and the elderly, were involved in our experiment. Each subject was first asked to sit on a seat in an 18°C chamber (uniform environment) for 40min and then sit on a heating seat in a 16°C chamber (non-uniform environment) for another 40min after 10min break. Subjects regional- and whole-body thermal sensation and comfort were surveyed by questionnaire and their skin temperatures were measured by wireless sensors. We statistically analyzed subjects thermal sensation and comfort and their skin temperatures in different age and gender groups and compared them between the uniform and non-uniform environments.nnnRESULTSnOverall thermal sensation and comfort votes were respectively neutral and just comfortable in 16°C chamber with personalized heating, which were significantly higher than those in 18°C chamber without heating (p<0.01). The effect of personalized heating on improving thermal sensation and comfort was consistent in subjects of different age and gender. However, adults and the females were more sensitive to the effect of personalized heating and felt cooler and less comfort than children/elderly and the males respectively. Variations of the regional thermal sensation/comfort across human body were consistent with those of skin temperature.nnnCONCLUSIONSnPersonalized heating significantly improved human thermal sensation and comfort in non-uniform cooler environment, probably due to the fact that it increased skin temperature. However, the link between thermal sensation/comfort and variations of skin temperature is rather complex and warrant further investigation.

Preconceptional and perinatal exposure to traffic-related air pollution and eczema in preschool children

BACKGROUNDnEvidence linking prenatal exposure to outdoor air pollution with eczema in early childhood is scare, and the role of components of air pollution and exposure timing remains unclear.nnnOBJECTIVESnWe investigated the association between exposure to air pollution during preconceptional and perinatal period and the risk of eczema in preschool children.nnnMETHODSnWe conducted a prospective cohort study of 2598 children aged 3-6 years in Changsha, China. The prevalence of eczema was assessed by a standardized health questionnaire administered by the parents. Individual exposures to nitrogen dioxide (NO2), sulfur dioxide (SO2) and particulate matter with an aerodynamic diameter≤10μm (PM10) during the 4th-6th and 1st-3rd month before pregnancy, entire pregnancy, and three trimesters were estimated by an inverse distance weighted (IDW) method based on concentrations measured at monitoring stations. Association between childhood eczema and exposure to air pollution was examined by logistic regression models in terms of odds ratio (OR) and 95% confidence interval (CI) for an interquartile range (IQR) increase in exposure.nnnRESULTSnLife-time prevalence of eczema in preschool children in Changsha was 28.6%. Childhood eczema was associated with traffic-related air pollutant NO2 during 3 months before pregnancy and entire pregnancy with adjusted ORs=1.19 (95% CI: 1.04-1.37) and 1.21 (95% CI: 1.03-1.42) respectively. The highest risk of eczema was observed for the 1st trimester exposure to NO2 [OR=1.26 (95% CI: 1.09-1.46)]. However, no association was detected for SO2 and PM10 exposure during any window. High-level exposure to NO2 during the whole time period significantly increased the effect of NO2 in all windows on eczema risk as compared with low-level exposure. Sensitivity analysis indicated that the association between both preconceptional and perinatal exposure to NO2 and childhood eczema was consistent and robust, and this association was modified by some personal, parental hereditary and indoor environmental factors.nnnCONCLUSIONnOur findings support the hypothesis that early childhood eczema is associated with exposure to traffic-related air pollutant during both preconceptional and perinatal period, especially at a high level of exposure.

Prenatal exposure to diurnal temperature variation and early childhood pneumonia

BACKGROUNDnChildhood pneumonia is one of the leading single causes of mortality and morbidity in children worldwide, but its etiology still remains unclear.nnnOBJECTIVEnWe investigate the association between childhood pneumonia and exposure to diurnal temperature variation (DTV) in different timing windows.nnnMETHODSnWe conducted a prospective cohort study of 2,598 children aged 3-6 years in Changsha, China. The lifetime prevalence of pneumonia was assessed by a questionnaire administered by the parents. Individual exposure to DTV during both prenatal and postnatal periods was estimated. Logic regression models was used to examine the association between childhood pneumonia and DTV exposure in terms of odds ratios (OR) and 95% confidence interval (CI).nnnRESULTSnLifetime prevalence of childhood pneumonia in preschool children in Changsha was high up to 38.6%. We found that childhood pneumonia was significantly associated with prenatal DTV exposure, with adjusted OR (95%CI) =1.19 (1.02-1.38), particularly during the second trimester. However, childhood pneumonia not associated with postnatal DTV exposure. Sensitivity analysis indicated that boys are more susceptible to the pneumonia risk of diurnal temperature variation than girls. We further observed that the prevalence of childhood pneumonia was decreased in recent years as DTV shrinked.nnnCONCLUSIONSnEarly childhood pneumonia was associated with prenatal exposure to the diurnal temperature variation (DTV) during pregnancy, particularly in the second trimester, which suggests fetal origin of childhood pneumonia.

Lifetime cancer risk assessment for inhalation exposure to di(2-ethylhexyl) phthalate (DEHP)

The plasticizer di(2-ethylhexyl) phthalate (DEHP) is ubiquitous in the environment and considered as carcinogen; however, the carcinogenic risk of human exposure to DEHP in the air via inhalation is lacking. A probabilistic incremental lifetime cancer risk (ILCR) model was implemented to quantitatively estimate the potential cancer risk of DEHP via human inhalation by using Monte Carlo simulation. We assessed the cancer risk in different age groups (children, adolescents, and adults) exposed to different DEHP concentrations (background low, indoor moderate, and occupational high) for different durations (2, 8, and 20xa0years). Results showed that the cancer risk of exposure to DEHP was below the acceptable limit (10−6) in the ambient air but was serious in indoor and occupational environments even at short exposure duration (2xa0years). The cancer risk of DEHP via inhalation in children was lower than that in adolescents and adults, but the risk in children via dermal and oral exposure to indoor dust and soft PVC toys should be considered. Sensitivity analysis indicated that the exposure concentration of DEHP was the strongest factor that influenced ILCR. Our work provides the evidence of cancer risk of DEHP via inhalation and highlights the risk in indoor and occupational environments.

The effects of PM2.5 on asthmatic and allergic diseases or symptoms in preschool children of six Chinese cities, based on China, Children, Homes and Health (CCHH) project

The urbanization and industrialization in China is accompanied by bad air quality, and the prevalence of asthma in Chinese children has been increasing in recent years. To investigate the associations between ambient PM2.5 levels and asthmatic and allergic diseases or symptoms in preschool children in China, we assigned PM2.5 exposure data from the Global Burden of Disease (GBD) project to 205 kindergartens at a spatial resolution of 0.1°xa0×xa00.1° in six cities in China (Shanghai, Nanjing, Chongqing, Changsha, Urumqi, and Taiyuan). A hierarchical multiple logistical regression model was applied to analyze the associations between kindergarten-level PM2.5 exposure and individual-level outcomes of asthmatic and allergic symptoms. The individual-level variables, including gender, age, family history of asthma and allergic diseases, breastfeeding, parental smoking, indoor dampness, interior decoration pollution, household annual income, and city-level variable-annual temperature were adjusted. A total of 30,759 children (average age 4.6 years, 51.7% boys) were enrolled in this study. Apart from family history, indoor dampness, and decoration as predominant risk factors, we found that an increase of 10xa0μg/m3 of the annual PM2.5 was positively associated with the prevalence of allergic rhinitis by an odds ratio (OR) of 1.20 (95% confidence interval [CI] 1.11, 1.29) and diagnosed asthma by OR of 1.10 (95% CI 1.03, 1.18). Those who lived in non-urban (vs. urban) areas were exposed to more severe indoor air pollution arising from biomass combustion and had significantly higher ORs between PM2.5 and allergic rhinitis and current rhinitis. Our study suggested that long-term exposure to PM2.5 might increase the risks of asthmatic and allergic diseases or symptoms in preschool children in China. Compared to those living in urban areas, children living in suburban or rural areas had a higher risk of PM2.5 exposure.

Common cold among pre-school children in China - associations with ambient PM10 and dampness, mould, cats, dogs, rats and cockroaches in the home environment

BACKGROUNDnThere is some evidence that dampness, mould and cockroaches can increase the risk of respiratory infections in children but few studies exist from China on this topic. Aim To study associations between domestic early life exposure to biological indoor factors (dampness, mould, cats, dogs, rats, cockroaches), cleaning habits and common cold among pre-school children across China.nnnMETHODSnChildren aged 3-6years (n=39,782) were recruited from randomly selected day care centres in seven cities in China. Data on common cold and prenatal and postnatal exposure to dampness, mould, windowpane condensation in wintertime (WPC), cats, dogs, cockroaches and rats were assessed by a parentally administered questionnaire. Data on annual ambient temperature and PM10 was assessed on city level. Associations between high frequency (>5 colds per year) and long duration (≥2weeks) of common colds in the past year and exposure were calculated by multilevel logistic regression.nnnRESULTSnA total of 9.2% had a high frequency and 11.9% had long duration of common cold. Exposure to mould (OR=1.38, 95% CI 1.24-1.53) and WPC (OR 1.23, 95%CI 1.13-1.33) at birth was associated with frequent common cold. Exposure to dogs at birth was associated with long duration of common cold. (OR=1.22, 95% CI 1.06-1.41). Exposure to mould (OR=1.36, 95% CI 1.22-1.54), WPC (OR=1.27, 95%CI 1.17-1.39) and water leakage (OR 1.34, 95% CI 1.20-1.49) in the current home was associated with frequent common cold. Presence of cockroaches were positively (OR=1.12, 95% CI 1.02-1.24) and presence of rats (OR=0.86, 95% CI 0.77-0.96) negatively associated with high frequency of common cold. Daily cleaning was negatively associated with frequent common cold (OR=0.89, 95% CI 0.81-0.97). Similar associations for mould, WPC, cockroaches and rats were found for long duration. Ambient PM10 (OR=1.21, 95% CI 1.21-1.35 per 10μg/m3) and temperature (OR=1.13, 95% CI 1.06-1.35 °C) on city level were associated with high frequency of common cold. Associations between cat keeping and high frequency of common cold were found only in southern China. Associations with cockroaches were stronger in northern China. Associations with dampness and mould were the same in the north and south.nnnCONCLUSIONSnIndoor mould, water damage, windowpane condensation, cockroaches and keeping cats or dogs as pets can be risk factors for common cold while daily cleaning can be protective factor. PM10 and a warmer climate zone can be other risk factors for common cold.

Maternal exposure to ambient air temperature during pregnancy and early childhood pneumonia

BACKGROUNDnPneumonia has been widely recognized as the leading cause of death in children worldwide, but its etiology still remains unclear.nnnOBJECTIVEnWe examined the association between maternal exposure to ambient air temperature during pregnancy and lifetime pneumonia in the offspring.nnnMETHODSnWe conducted a cohort study of 2598 preschool children aged 3-6 years in Changsha, China. The lifetime prevalence of pneumonia was assessed using questionnaire. We backwards estimated each childs exposure to air temperature during prenatal and postnatal periods. Multiple regression model was used to examine the association between childhood pneumonia and exposure to air temperature in terms of odd ratios (OR) and 95% confidence interval (CI).nnnRESULTSnPrevalence of childhood pneumonia in Changsha was high up to 38.6%. We found that childhood pneumonia was significantly associated with prenatal exposure to air temperature, with adjusted OR (95% CI) = 1.77 (1.23-2.54) for an interquartile range (IQR) increase in temperature, particularly during the second trimester with adjusted OR (95% CI) = 2.26 (1.32-3.89). Boys are more susceptible to the risk of pneumonia due to air temperature than girls. We further observed that maternal exposure to extreme heat days during pregnancy increased the risk of pneumonia in the offspring.nnnCONCLUSIONSnMaternal exposure to air temperature during pregnancy, particularly the second trimester, was associated with pneumonia in the children, providing the evidence for fetal origins of pneumonia.

Experimental and numerical study of the performance of upper-room ultraviolet germicidal irradiation with the effective Z-value of airborne bacteria

ABSTRACT Upper-room ultraviolet germicidal irradiation (UR-UVGI) is recommended for the defense against airborne pathogens in poorly ventilated rooms in public buildings or high risk environments, such as hospitals. Currently, there are few studies on the performance of UR-UVGI with the effective bacteria susceptibility constant (eZ-value) obtained from UR-UVGI experiment. In this study, the Eulerian model for the inactivation of UVGI was improved to consider the difference between exposure time and computational time, and was validated by our previous experiments. The method was applied to study numerically the performance of the UR-UVGI for 3, 6, and 10 air changes per hour (ACH) with the application of the eZ-value of airborne bacteria. Moreover, the eZ-values of commonly found bacteria, including Serratia marcescens, Staphylococcus epidermidis, Pseudomonas alcaligenes, and Micrococcus luteus, were obtained from a series of experiments in a full-scale environmental chamber equipped with a UR-UVGI fixture. The eZ-values were 0.0983, 0.0586, 0.0476, and 0.0115 m2/J, respectively. Compared with the data in the literature, these eZ-values of the tested bacteria are different from the Z-values obtained from single-pass UVGI. The simulation results show that UR-UVGI exhibited the highest inactivation efficiency on S. marcescens among the tested bacteria in this study. The percentage of bacteria inactivated by UR-UVGI decreased as the ventilation rate increased. The bacteria concentration in the breathing zone under low ventilation rate could be decreased using UR-UVGI. The findings demonstrate that high indoor air quality can be achieved with the application of UR-UVGI without the need to maintain high ventilation rate. Copyright

Particle deposition in tracheobronchial airways of an infant, child and adult

BACKGROUNDnParticle deposition in human airways is important for assessing both health effects of inhaled particles and therapeutic efficacy of inhaled drug aerosols, but is not well understood for infants and children.nnnOBJECTIVEnWe investigate particle deposition in infants and children by using computational fluid dynamics (CFD), and compare this with particle deposition in adults.nnnMETHODSnWe chose three population age groups: 7-month infant, 4-year old child, and 20-year old adult. Both airway structures and breathing conditions are considered to vary as a human grows from infancy to adulthood. We investigated deposition of micron-size particles (1-10μm) in both the upper (G3-G6) and lower (G9-G12) tracheobronchial (TB) airways under sedentary conditions.nnnRESULTSnWe found that particle deposition in both upper and lower airways is the highest in an infant, next in a child, and lowest in an adult. As age increases, particle deposition decreases in the upper airways but increases in the lower. For infants, inertial impaction is the dominant deposition mechanism, thus particles are deposited more in the upper airways than in the lower. However, particles are deposited more in the lower airways than in the upper in adults, as gravitational sedimentation is the dominant deposition mechanism.nnnCONCLUSIONnGiven the differences in the airway structure and particle deposition mechanisms, particle deposition in infants and children differs from that in adults, not only in the efficiency of deposition but also in the site. Our findings provide evidence that children are not small adults.

Parental stress and air pollution increase childhood asthma in China

Background Although air pollution and social stress may independently increase childhood asthma, little is known on their synergistic effect on asthma, particularly in China with high levels of stress and air pollution. Objectives To examine associations between exposure to a combination of parental stress and air pollution and asthma prevalence in children. Methods We conducted a cohort study of 2406 preschool children in Changsha (2011–2012). A questionnaire was used to collect children’s lifetime prevalence of asthma and their parental stress. Parental socioeconomic and psychosocial stresses were respectively defined in terms of housing size and difficulty concentrating. Children’s exposure to ambient air pollutants was estimated using concentrations measured at monitoring stations. Associations between exposure to parental stress and air pollution and childhood asthma were estimated by multiple logistic regression models using odds ratio (OR) and 95% confidence interval (CI). Results Life time prevalence of asthma in preschool children (6.7%) was significantly associated with parental socioeconomic and psychosocial stresses with OR (95% CI) respectively 1.48 (1.02–2.16) and 1.64 (1.00–2.71). Asthma was also associated with exposure to air pollutants, with adjusted OR (95% CI) during prenatal and postnatal periods respectively 1.43 (1.10–1.86) and 1.35 (1.02–1.79) for SO2 and 1.61 (1.19–2.18) and 1.76 (1.19–2.61) for NO2. The association with air pollution was significant only in children exposed to high parental stress, the association with parental stress was significant only in children exposed to high air pollution, and the association was the strongest in children exposed to a combination of parental stress and air pollution. Sensitivity analysis showed that the synergistic effects of parental stress and air pollution on childhood asthma were stronger in boys. Conclusions Parental stress and air pollution were synergistically associated with increased childhood asthma, indicating a common biological effect of parental stress and air pollution during both prenatal and postnatal periods. Graphical abstract Figure. No Caption available. HighlightsLittle is known about the effect of stress‐pollution interaction on childhood asthma.We examined associations of parental stress and air pollution with childhood asthma in China.Association of air pollution with asthma is significant in children exposed to high parental stress.Association of parental stress with asthma is significant in children exposed to high air pollution.Interactive effect of stress and air pollution on asthma indicates a common biological pathway.